/*
 * Copyright 2011 CraneLeeon authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */
package org.crane.webtemplate;

import java.io.IOException;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Hashtable;
import java.util.Map;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 *
 * @author CraneLeeon
 */
public class PrepareAndExecuteFilter implements Filter {
    private static final Log logger = LogFactory.getLog(PrepareAndExecuteFilter.class);
    public static String CONFIG_FILE_URI = "web-template.xml";
    public static Boolean DEBUG = false;
    protected static ObjectContext objectContext;
    public static ObjectContext getObjectContext(){
        return objectContext;
    }
    protected static final Map siteMap = new Hashtable();
    public static Map<String, String> getSiteMap(){
        return siteMap;
    }
    
    // The filter configuration object we are associated with.  If
    // this value is null, this filter instance is not currently
    // configured. 
    private FilterConfig filterConfig = null;
    
    public PrepareAndExecuteFilter() {
    }    
    
    private void doBeforeProcessing(ServletRequest request, ServletResponse response)
            throws IOException, ServletException {
        if (DEBUG) {
            logger.debug("PrepareAndExecuteFilter:DoBeforeProcessing");
        }
        
    }    
    
    private void doAfterProcessing(ServletRequest request, ServletResponse response)
            throws IOException, ServletException {
        
    }

    /**
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     * @param chain The filter chain we are processing
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet error occurs
     */
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain)
            throws IOException, ServletException {
        
        if (DEBUG) {
            logger.debug("PrepareAndExecuteFilter:doFilter()");
        }
        
        doBeforeProcessing(request, response);
        
        
        Throwable problem = null;
        try {
            chain.doFilter(request, response);
        } catch (Throwable t) {
            // If an exception is thrown somewhere down the filter chain,
            // we still want to execute our after processing, and then
            // rethrow the problem after that.
            problem = t;
            if (DEBUG) {
                logger.debug(t);
            }
        }
        
        doAfterProcessing(request, response);

        // If there was a problem, we want to rethrow it if it is
        // a known type, otherwise log it.
        if (problem != null) {
            if (problem instanceof ServletException) {
                throw (ServletException) problem;
            }
            if (problem instanceof IOException) {
                throw (IOException) problem;
            }
            sendProcessingError(problem, response);
        }
    }

    /**
     * Return the filter configuration object for this filter.
     */
    public FilterConfig getFilterConfig() {
        return (this.filterConfig);
    }

    /**
     * Set the filter configuration object for this filter.
     *
     * @param filterConfig The filter configuration object
     */
    public void setFilterConfig(FilterConfig filterConfig) {
        this.filterConfig = filterConfig;
    }

    /**
     * Destroy method for this filter 
     */
    public void destroy() {        
    }

    /**
     * Init method for this filter 
     */
    public void init(FilterConfig filterConfig) {        
        this.filterConfig = filterConfig;
        if (filterConfig != null) {
            DEBUG = Boolean.valueOf(this.filterConfig.getInitParameter("DEBUG"));
            if (DEBUG) {                
                logger.debug("PrepareAndExecuteFilter:Initializing filter");
            }
            String newcfg_uri = this.filterConfig.getInitParameter("CONFIG_FILE_URI");
            if(newcfg_uri != null) CONFIG_FILE_URI= newcfg_uri;
            objectContext = new ObjectContext(CONFIG_FILE_URI);
        }
    }
    
     /**
     * Return a String representation of this object.
     */
    @Override
    public String toString() {
        if (filterConfig == null) {
            return ("PrepareAndExecuteFilter()");
        }
        StringBuffer sb = new StringBuffer("PrepareAndExecuteFilter(");
        sb.append(filterConfig);
        sb.append(")");
        return (sb.toString());
    }
    
    private void sendProcessingError(Throwable t, ServletResponse response) {
        String stackTrace = getStackTrace(t);        
        
        if (stackTrace != null && !stackTrace.equals("")) {
            try {
                response.setContentType("text/html");
                PrintStream ps = new PrintStream(response.getOutputStream());
                PrintWriter pw = new PrintWriter(ps);                
                pw.print("<html>\n<head>\n<title>Error</title>\n</head>\n<body>\n"); //NOI18N

                // PENDING! Localize this for next official release
                pw.print("<h1>The resource did not process correctly</h1>\n<pre>\n");                
                pw.print(stackTrace);                
                pw.print("</pre></body>\n</html>"); //NOI18N
                pw.close();
                ps.close();
                response.getOutputStream().close();
            } catch (Exception ex) {
            }
        } else {
            try {
                PrintStream ps = new PrintStream(response.getOutputStream());
                t.printStackTrace(ps);
                ps.close();
                response.getOutputStream().close();
            } catch (Exception ex) {
            }
        }
    }
    
    public static String getStackTrace(Throwable t) {
        String stackTrace = null;
        try {
            StringWriter sw = new StringWriter();
            PrintWriter pw = new PrintWriter(sw);
            t.printStackTrace(pw);
            pw.close();
            sw.close();
            stackTrace = sw.getBuffer().toString();
        } catch (Exception ex) {
        }
        return stackTrace;
    }
    
    public void log(String msg) {
        filterConfig.getServletContext().log(msg);        
    }
}
